Durable guides and focused references for monitoring email authentication and website security. Written and maintained by AuthDrift.
A scan of every active Y Combinator company domain: how many publish no DMARC or a monitoring-only policy, how close their SPF records are to the 10-lookup limit, and how many websites send HSTS and a Content-Security-Policy.
Why organizations stall in DMARC monitoring mode, what aggregate reports can and cannot prove, and how to move toward enforcement without breaking legitimate mail.
Find a DKIM selector in message headers or provider settings, query the correct DNS name, and diagnose missing, revoked, or weak keys.
Compare DMARC monitoring and enforcement policies, understand pct and subdomain behavior, and move toward reject without blocking legitimate mail.
A repeatable domain monitoring checklist for agencies and MSPs covering ownership, email authentication, TLS, security headers, alerting, and evidence.
Learn how continuous SPF, DKIM, and DMARC monitoring detects configuration drift before it becomes a deliverability or spoofing incident.
Monitor HSTS, CSP, frame protection, MIME sniffing, referrer, permissions, TLS, and certificate posture without treating headers as a vulnerability scan.
Understand which SPF mechanisms count toward the 10-lookup limit, how recursive includes cause failures, and how to fix an oversized SPF policy safely.